Gas analysis can be an important means for detecting the presence and concentration of certain chemicals in the gas and determining the meaning of the particular combination of chemicals present. In health care, for example, the presence of certain volatile organic compounds (VOCs) in exhaled human breath are correlated to certain diseases, such as pneumonia, pulmonary tuberculosis (TB), asthma, lung cancer, liver diseases, kidney diseases, etc. The correlations are especially evidential for lung-related diseases. In other applications, gas analysis can be used to determine the presence of dangerous substances incompatible with human presence, such as methane, carbon monoxide or carbon dioxide in a mine.
Current gas analytical systems still rely heavily on large and expensive laboratory instruments, such as gas chromatography (GC) and mass spectrometry (MS). Most of these instruments (mass spectrometers in particular) have operational characteristics that prevent significant reductions in their size, meaning that current gas analysis systems are large and expensive bench devices. In addition to being expensive and unwieldy, the large size of current gas analysis devices makes widespread use of these instruments impossible.
GC column coatings are usually optimized for specific temperatures and chemicals, so that no single GC can separate a large array of chemicals, even by varying its temperature. Because existing GCs are large, heavy units housed in labs, a carrier gas with many chemicals may need to be sent to multiple locations for separation, which substantially increases cost. The gas analyte/volatile organic compound (VOC) concentration distribution (spectrum) usually is broadened when injected into the GC column. In the application of portable gas analysis, there is no viable solution to sharpen the analyte/VOC spectrum without loss of detection limit. Moreover, the current column focusing can only be achieved by direct impinging liquid nitrogen or dry ice to a small section of bulky GC column for focusing effect. Such approach is expensive and cannot be implemented as a portable gas analysis system.